Electronic vapor provision systems such as e-cigarettes generally contain a reservoir of liquid, typically nicotine, which is to be vaporized or otherwise converted into an aerosol. For example, when a user inhales on the device, a heater is activated to vaporize a small amount of liquid, which is therefore inhaled by the user. More particularly, such devices are usually provided with one or more air inlet holes located away from the mouthpiece. When a user sucks on the mouthpiece, air is drawn in through the inlet holes and past the vapor source, such as the heater supplied with nicotine or other liquid from a cartridge.
The amount of power provided to the heater may be controlled for operational reasons. For example, WO 2012/109371 describes a device which has different operating modes, and the selection of operating mode depends on the interval between successive puffs (since for a short interval, the heater may already be warm from a previous puff). WO 2013/060784 describes a device which reduces the power supplied to the heater towards the end of an inhalation in order to reduce unwanted condensation of aerosol within the device.
In some known devices, the user can exercise a certain degree of control over the operation of an electronic vapor provision system. Such control may, for example, allow a user to alter the power delivered to the heater by rotating a dial. However, existing mechanisms for controlling a user experience are still somewhat limited in terms of flexibility, responsiveness and ease of use.